program nGon;

{$APPTYPE CONSOLE}

uses
  SysUtils;

var
  n, i, j, dS, x0, y0, dS0: Integer;
  mass1, mass2 : array of Integer;
  fin: TextFile;

begin
  AssignFile (fin, 'input.txt');
  Reset (fin);
  Readln (fin, n);
  SetLength (mass1, n);
  SetLength (mass2, n);
  for j:=0 to n+1 do
  begin
    for i:= 0 to n+1 do
    begin
      if i mod 2 = 0 then
      begin
        Read (fin, mass1[j]);
      end else begin
        Read (fin, mass2[j]);
      end;
    end;
  end;
  Readln (fin);
  read (fin, x0, y0);
  for i:= 1 to n-1 do
  begin
     dS:=dS+abs((mass1[0]-mass1[i+2])*(mass2[i+1]-mass2[i+2])-(mass1[i+1]-mass1[i+2])*(mass2[0]-mass2[i+2]));
  end;
  for i:=0 to n-1 do
  begin
     dS0:=dS0+abs((x0-mass1[i+1])*(mass2[i]-mass2[i+1])-(mass1[i]-mass1[i+1])*(y0-mass2[i+1]));
  end;
  if (dS=dS0) then
  begin
    Writeln ('yes.');
  end else begin
    Writeln ('no.');
  end;
  Readln;
  CloseFile (fin);
end.
